The invention relates generally to sorting apparatus for collating sheets into sets and is particularly adapted for use, although not exclusively, with or as part of an electrophotographic printing machine.
In an electrophotographic printing machine, a photoconductive member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charge thereon in the irradiated area. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document being reproduced. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer mixture into contact therewith. Generally, the developer mixture comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. Finally, the copy sheet is heated to permanently affix the toner particles thereto in image configuration.
Frequently, it is highly desirable to reproduce a plurality of copies of the same original document. Moreover, if several original documents are reproduced, it is desirable to form a plurality of collated sets of copies. This may be achieved by the utilization of a sorting apparatus. Generally, the sorting apparatus comprises a plurality of bins or trays wherein each tray is designed to collect one set of copies of the original document. A variety of sorters are known in the art. One typical sorter employs tray members which are spaced apart and extend in a linear row. Another type of sorting apparatus has a tray member extending radially outwardly from an axis of rotation. These are the two basic types of sorters generally used commercially, i.e. a linear type and a rotary type.
Copy sheets may be collected in the trays of the sorter in a number of ways. The most common technique is to utilize a sheet transport to advance the copy sheets past the tray openings and deflection fingers to guide the sheets from the transport into the respective tray. Another technique comprises the use of a moving deflection finger which travels from tray to tray to deflect the copy sheet into the respective tray. Yet still another approach is to move the trays past the sheet ejecting portion of the transport. In this way, the trays collect successive sheets therein.